net/l3mdev/l3mdev.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/l3mdev/l3mdev.c - L3 master device implementation
   4  * Copyright (c) 2015 Cumulus Networks
   5  * Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
   6  */
   7
   8 #include <linux/netdevice.h>
   9 #include <net/fib_rules.h>
  10 #include <net/l3mdev.h>
  11
  12 static DEFINE_SPINLOCK(l3mdev_lock);
  13
  14 struct l3mdev_handler {
  15         lookup_by_table_id_t dev_lookup;
  16 };
  17
  18 static struct l3mdev_handler l3mdev_handlers[L3MDEV_TYPE_MAX + 1];
  19
  20 static int l3mdev_check_type(enum l3mdev_type l3type)
  21 {
  22         if (l3type <= L3MDEV_TYPE_UNSPEC || l3type > L3MDEV_TYPE_MAX)
  23                 return -EINVAL;
  24
  25         return 0;
  26 }
  27
  28 int l3mdev_table_lookup_register(enum l3mdev_type l3type,
  29                                  lookup_by_table_id_t fn)
  30 {
  31         struct l3mdev_handler *hdlr;
  32         int res;
  33
  34         res = l3mdev_check_type(l3type);
  35         if (res)
  36                 return res;
  37
  38         hdlr = &l3mdev_handlers[l3type];
  39
  40         spin_lock(&l3mdev_lock);
  41
  42         if (hdlr->dev_lookup) {
  43                 res = -EBUSY;
  44                 goto unlock;
  45         }
  46
  47         hdlr->dev_lookup = fn;
  48         res = 0;
  49
  50 unlock:
  51         spin_unlock(&l3mdev_lock);
  52
  53         return res;
  54 }
  55 EXPORT_SYMBOL_GPL(l3mdev_table_lookup_register);
  56
  57 void l3mdev_table_lookup_unregister(enum l3mdev_type l3type,
  58                                     lookup_by_table_id_t fn)
  59 {
  60         struct l3mdev_handler *hdlr;
  61
  62         if (l3mdev_check_type(l3type))
  63                 return;
  64
  65         hdlr = &l3mdev_handlers[l3type];
  66
  67         spin_lock(&l3mdev_lock);
  68
  69         if (hdlr->dev_lookup == fn)
  70                 hdlr->dev_lookup = NULL;
  71
  72         spin_unlock(&l3mdev_lock);
  73 }
  74 EXPORT_SYMBOL_GPL(l3mdev_table_lookup_unregister);
  75
  76 int l3mdev_ifindex_lookup_by_table_id(enum l3mdev_type l3type,
  77                                       struct net *net, u32 table_id)
  78 {
  79         lookup_by_table_id_t lookup;
  80         struct l3mdev_handler *hdlr;
  81         int ifindex = -EINVAL;
  82         int res;
  83
  84         res = l3mdev_check_type(l3type);
  85         if (res)
  86                 return res;
  87
  88         hdlr = &l3mdev_handlers[l3type];
  89
  90         spin_lock(&l3mdev_lock);
  91
  92         lookup = hdlr->dev_lookup;
  93         if (!lookup)
  94                 goto unlock;
  95
  96         ifindex = lookup(net, table_id);
  97
  98 unlock:
  99         spin_unlock(&l3mdev_lock);
 100
 101         return ifindex;
 102 }
 103 EXPORT_SYMBOL_GPL(l3mdev_ifindex_lookup_by_table_id);
 104
 105 /**
 106  *      l3mdev_master_ifindex_rcu - get index of L3 master device
 107  *      @dev: targeted interface
 108  */
 109
 110 int l3mdev_master_ifindex_rcu(const struct net_device *dev)
 111 {
 112         int ifindex = 0;
 113
 114         if (!dev)
 115                 return 0;
 116
 117         if (netif_is_l3_master(dev)) {
 118                 ifindex = dev->ifindex;
 119         } else if (netif_is_l3_slave(dev)) {
 120                 struct net_device *master;
 121                 struct net_device *_dev = (struct net_device *)dev;
 122
 123                 /* netdev_master_upper_dev_get_rcu calls
 124                  * list_first_or_null_rcu to walk the upper dev list.
 125                  * list_first_or_null_rcu does not handle a const arg. We aren't
 126                  * making changes, just want the master device from that list so
 127                  * typecast to remove the const
 128                  */
 129                 master = netdev_master_upper_dev_get_rcu(_dev);
 130                 if (master)
 131                         ifindex = master->ifindex;
 132         }
 133
 134         return ifindex;
 135 }
 136 EXPORT_SYMBOL_GPL(l3mdev_master_ifindex_rcu);
 137
 138 /**
 139  *      l3mdev_master_upper_ifindex_by_index_rcu - get index of upper l3 master
 140  *                                             device
 141  *      @net: network namespace for device index lookup
 142  *      @ifindex: targeted interface
 143  */
 144 int l3mdev_master_upper_ifindex_by_index_rcu(struct net *net, int ifindex)
 145 {
 146         struct net_device *dev;
 147
 148         dev = dev_get_by_index_rcu(net, ifindex);
 149         while (dev && !netif_is_l3_master(dev))
 150                 dev = netdev_master_upper_dev_get_rcu(dev);
 151
 152         return dev ? dev->ifindex : 0;
 153 }
 154 EXPORT_SYMBOL_GPL(l3mdev_master_upper_ifindex_by_index_rcu);
 155
 156 /**
 157  *      l3mdev_fib_table_rcu - get FIB table id associated with an L3
 158  *                             master interface
 159  *      @dev: targeted interface
 160  */
 161
 162 u32 l3mdev_fib_table_rcu(const struct net_device *dev)
 163 {
 164         u32 tb_id = 0;
 165
 166         if (!dev)
 167                 return 0;
 168
 169         if (netif_is_l3_master(dev)) {
 170                 if (dev->l3mdev_ops->l3mdev_fib_table)
 171                         tb_id = dev->l3mdev_ops->l3mdev_fib_table(dev);
 172         } else if (netif_is_l3_slave(dev)) {
 173                 /* Users of netdev_master_upper_dev_get_rcu need non-const,
 174                  * but current inet_*type functions take a const
 175                  */
 176                 struct net_device *_dev = (struct net_device *) dev;
 177                 const struct net_device *master;
 178
 179                 master = netdev_master_upper_dev_get_rcu(_dev);
 180                 if (master &&
 181                     master->l3mdev_ops->l3mdev_fib_table)
 182                         tb_id = master->l3mdev_ops->l3mdev_fib_table(master);
 183         }
 184
 185         return tb_id;
 186 }
 187 EXPORT_SYMBOL_GPL(l3mdev_fib_table_rcu);
 188
 189 u32 l3mdev_fib_table_by_index(struct net *net, int ifindex)
 190 {
 191         struct net_device *dev;
 192         u32 tb_id = 0;
 193
 194         if (!ifindex)
 195                 return 0;
 196
 197         rcu_read_lock();
 198
 199         dev = dev_get_by_index_rcu(net, ifindex);
 200         if (dev)
 201                 tb_id = l3mdev_fib_table_rcu(dev);
 202
 203         rcu_read_unlock();
 204
 205         return tb_id;
 206 }
 207 EXPORT_SYMBOL_GPL(l3mdev_fib_table_by_index);
 208
 209 /**
 210  *      l3mdev_link_scope_lookup - IPv6 route lookup based on flow for link
 211  *                           local and multicast addresses
 212  *      @net: network namespace for device index lookup
 213  *      @fl6: IPv6 flow struct for lookup
 214  *      This function does not hold refcnt on the returned dst.
 215  *      Caller must hold rcu_read_lock().
 216  */
 217
 218 struct dst_entry *l3mdev_link_scope_lookup(struct net *net,
 219                                            struct flowi6 *fl6)
 220 {
 221         struct dst_entry *dst = NULL;
 222         struct net_device *dev;
 223
 224         WARN_ON_ONCE(!rcu_read_lock_held());
 225         if (fl6->flowi6_oif) {
 226                 dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
 227                 if (dev && netif_is_l3_slave(dev))
 228                         dev = netdev_master_upper_dev_get_rcu(dev);
 229
 230                 if (dev && netif_is_l3_master(dev) &&
 231                     dev->l3mdev_ops->l3mdev_link_scope_lookup)
 232                         dst = dev->l3mdev_ops->l3mdev_link_scope_lookup(dev, fl6);
 233         }
 234
 235         return dst;
 236 }
 237 EXPORT_SYMBOL_GPL(l3mdev_link_scope_lookup);
 238
 239 /**
 240  *      l3mdev_fib_rule_match - Determine if flowi references an
 241  *                              L3 master device
 242  *      @net: network namespace for device index lookup
 243  *      @fl:  flow struct
 244  *      @arg: store the table the rule matched with here
 245  */
 246
 247 int l3mdev_fib_rule_match(struct net *net, struct flowi *fl,
 248                           struct fib_lookup_arg *arg)
 249 {
 250         struct net_device *dev;
 251         int rc = 0;
 252
 253         /* update flow ensures flowi_l3mdev is set when relevant */
 254         if (!fl->flowi_l3mdev)
 255                 return 0;
 256
 257         rcu_read_lock();
 258
 259         dev = dev_get_by_index_rcu(net, fl->flowi_l3mdev);
 260         if (dev && netif_is_l3_master(dev) &&
 261             dev->l3mdev_ops->l3mdev_fib_table) {
 262                 arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
 263                 rc = 1;
 264         }
 265
 266         rcu_read_unlock();
 267
 268         return rc;
 269 }
 270
 271 void l3mdev_update_flow(struct net *net, struct flowi *fl)
 272 {
 273         struct net_device *dev;
 274
 275         rcu_read_lock();
 276
 277         if (fl->flowi_oif) {
 278                 dev = dev_get_by_index_rcu(net, fl->flowi_oif);
 279                 if (dev) {
 280                         if (!fl->flowi_l3mdev)
 281                                 fl->flowi_l3mdev = l3mdev_master_ifindex_rcu(dev);
 282
 283                         /* oif set to L3mdev directs lookup to its table;
 284                          * reset to avoid oif match in fib_lookup
 285                          */
 286                         if (netif_is_l3_master(dev))
 287                                 fl->flowi_oif = 0;
 288                         goto out;
 289                 }
 290         }
 291
 292         if (fl->flowi_iif > LOOPBACK_IFINDEX && !fl->flowi_l3mdev) {
 293                 dev = dev_get_by_index_rcu(net, fl->flowi_iif);
 294                 if (dev)
 295                         fl->flowi_l3mdev = l3mdev_master_ifindex_rcu(dev);
 296         }
 297
 298 out:
 299         rcu_read_unlock();
 300 }
 301 EXPORT_SYMBOL_GPL(l3mdev_update_flow);